JP5920410B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water supply apparatus, and more particularly to a latent heat recovery type hot water supply apparatus capable of heating hot water by recovering latent heat of combustion gas.

  In addition to the primary heat exchanger that mainly recovers the sensible heat of the combustion gas, the latent heat recovery type hot-water supply device has a secondary heat exchanger that mainly recovers the latent heat and condenses the water vapor contained in the combustion gas. Therefore, heat of condensation (latent heat) can be obtained, so that high heat conversion efficiency can be achieved.

  In such a latent heat recovery type hot water supply apparatus, drain (condensation water) is generated by condensation of water vapor in the combustion gas in the secondary heat exchanger. At this time, the combustion gas includes nitrogen oxides produced by the reaction of nitrogen and oxygen in the air by combustion, sulfur oxides produced by the sulfur content of the fuel reacting with oxygen by combustion, etc. It is. Therefore, the generated drain is strongly acidic due to these nitrogen oxides and sulfur oxides.

  The drain generated in the secondary heat exchanger is normally neutralized by a neutralizer disposed in the drain discharge path and then discharged to the outside through the drain discharge path. In the hot water supply apparatus provided with such a drain discharge path, the flow path of the combustion gas and the drain discharge path are configured to communicate with each other.

  For this reason, when an exhaust push type hot water supply device that exhausts combustion gas to the outside by pushing outside air with a fan is installed indoors, the inside of the secondary heat exchanger becomes positive pressure, Thus, there is a concern that the combustion gas to be discharged outside the room is discharged into the room in which the hot water supply apparatus is installed through the drain discharge path.

  Further, for example, in the case of an exhaust suction type latent heat recovery type hot water supply device as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 60-186617) and Patent Document 2 (Japanese Patent Publication No. 6-35897), Since the fan is installed downstream of the heat exchanger, the internal pressure of the secondary heat exchanger becomes negative due to the suction pressure of the fan, and the outside air flows back into the secondary heat exchanger via the drain discharge path. There is a risk that drainage is difficult to be discharged from the secondary heat exchanger.

  Therefore, in such a hot water supply apparatus, for example, a plurality of rooms are provided in a drain tank provided in the drain discharge path, and the holes communicating with the rooms are filled with drain and sealed with water. Measures to eliminate are adopted. Such a water seal structure of the drain discharge path in the latent heat recovery type hot water supply apparatus is disclosed in, for example, Patent Document 3 (Japanese Patent Laid-Open No. 2008-298367) and Patent Document 4 (Japanese Patent Laid-Open No. 2013-160453). Yes.

JP-A-60-186617 Japanese Patent Publication No. 6-35897 JP 2008-298367 A JP 2013-160453 A

  However, even with a hot water supply device having a drain discharge path having a water sealing mechanism, a trial operation of a new hot water supply device, a hot water supply device that has not been used for a long period of time, hot water supply that has been drained for maintenance and freeze prevention When restarting a device or the like, during the period from the start of operation until the drain discharge path is sealed with water, the exhaust gas is discharged into the chamber in the above-described exhaust push-type latent heat recovery type hot water supply device, or the exhaust suction method. The problem that drain becomes difficult to be discharged | emitted from the secondary heat exchanger in this latent heat recovery type hot water supply apparatus will arise.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a drain discharge path having a water sealing mechanism, and to enter the combustion gas chamber even during a period until the drain discharge path is sealed. It is an object to provide a latent heat recovery type hot water supply apparatus that does not cause a problem that it becomes difficult to discharge the drainage or drainage from the secondary heat exchanger.

  A hot water supply apparatus of the present invention is a latent heat recovery type hot water supply apparatus capable of heating hot water by recovering the latent heat of combustion gas, and a burner for generating the combustion gas by burning fuel gas in a combustion region; A heat exchanger that heats hot water flowing through the heat exchange with the combustion gas generated in the burner, a fan that supplies air to the burner, and a drain that is generated by collecting latent heat in the heat exchanger In order to discharge the heat to the outside of the heat exchanger, a drain discharge path connected to the heat exchanger. The drain discharge path has a water seal structure that is sealed with the drain. The fan that supplies air to the burner is a concept that includes both a type in which air is supplied to the burner when the fan draws air and a type in which air is supplied to the burner when the fan pushes air. It is.

  Furthermore, the hot water supply apparatus of the present invention includes a water seal determination unit that performs permission determination that the drain discharge path is sealed with water and the hot water supply device operates in a normal mode, and the water seal determination unit includes the permission determination. Until the operation is performed, a control unit that issues a command so that the burner performs an intermittent operation. In this way, by intermittently operating the burner during the period until the drain discharge path is sealed with water, it is possible to suppress problems such as discharge of combustion gas into the room and difficulty in draining from the secondary heat exchanger. Can do.

  In the burner, the combustion region is composed of a plurality of unit regions that can be controlled independently so that the amount of combustion gas generated can be changed according to the required hot water supply capacity. Until the determination unit performs the permission determination, it is preferable to issue a command to the burner so that the entire unit region is combusted. In this way, by maintaining the combustion state of all the combustion pipes, the amount of drain generation is maximized, so that the drain discharge path can be quickly sealed with water. That is, even when the water seal of the drain discharge path is released, it is possible to quickly exhibit the desired hot water supply capacity as usual.

  The burner is configured to be able to adjust the supply amount of the fuel gas to the combustion region, and the control unit supplies the fuel gas until the water seal determination unit makes the permission determination. Preferably, the burner is commanded so that the amount is maximized. In this way, by maintaining the combustion state at the maximum capacity, the amount of drain generation is maximized, so that the drain discharge path can be quickly sealed with water. That is, even when the water seal of the drain discharge path is released, it is possible to quickly exhibit the desired hot water supply capacity as usual.

  The water seal determination unit includes at least one selected from the group consisting of a supply amount of the fuel gas to the combustion region, a water temperature supplied to the hot water supply device, and a hot water temperature discharged from the hot water supply device. It is preferable that the permission determination is performed on the condition that the estimated drain discharge amount calculated by using has reached a predetermined threshold value or more. Thereby, it becomes possible to perform permission determination automatically by the water seal determination part.

  The fan is disposed downstream of the heat exchanger in the flow direction of the combustion gas, and is configured to draw air into the burner, and is downstream of the heat exchanger in the flow direction of the combustion gas. The exhaust gas temperature detector further measures the temperature of the combustion gas, and the water seal determination unit shows an increasing tendency that the temperature of the combustion gas measured by the exhaust gas temperature detector exceeds a predetermined threshold value. It is preferable to perform the permission determination on the condition. In such an exhaust suction type hot water supply apparatus, the problem that drain is difficult to be discharged from the secondary heat exchanger is suppressed by intermittently operating the burner during the period until the drain discharge path is sealed with water. Can do. In addition, the permission determination can be automatically performed by the water seal determination unit.

  The fan may be arranged upstream of the heat exchanger in the flow direction of the combustion gas so as to push air into the burner. In this case, the problem of exhausting the combustion gas to the outside (for example, the room) can be suppressed by intermittently operating the burner during the period until the drain discharge path is sealed with water.

  According to the present invention, a drain discharge path having a water sealing mechanism is provided, and even during a period until the drain discharge path is sealed, it is difficult for the combustion gas to be discharged into the room or from the secondary heat exchanger. Thus, it is possible to provide a latent heat recovery type hot water supply apparatus that does not cause the problem of becoming.

It is a front view which shows roughly the structure of the hot water supply apparatus in Embodiment 1. FIG. It is a partial cross section side view which shows the structure of the hot water supply apparatus shown in FIG. It is a front view which shows roughly the structure of the hot water supply apparatus in Embodiment 2. FIG. FIG. 2 is a cross-sectional view schematically showing a configuration of a drain tank in the first embodiment. It is a perspective view which shows roughly the structure of the burner in Embodiment 1, Comprising: It is a disassembled perspective view which removes and shows the wall surface of a burner case. It is a disassembled perspective view which removes and shows a part of combustion pipe from the disassembled perspective view of FIG. FIG. 3 is a perspective view schematically showing an example of the configuration of a combustion tube in the first embodiment. FIG. 3 is a block diagram for explaining a configuration of a control unit in the first embodiment. 4 is a flowchart for explaining the operation of the burner in the first embodiment. 3 is a timing chart for explaining the operation of the burner in the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals represent the same or corresponding parts. In addition, dimensional relationships such as length, width, thickness, and depth are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensional relationships.

<Embodiment 1>
The structure of the hot water supply apparatus in Embodiment 1 of this invention is demonstrated with reference to FIGS.

  Referring mainly to FIGS. 1 and 2, hot water supply apparatus 100 of the present embodiment is an exhaust suction combustion type latent heat recovery type hot water supply apparatus. The hot water supply apparatus 100 includes a housing 1, a burner 2, a primary heat exchanger 3, a secondary heat exchanger 4, an exhaust box 5, a fan 6, an exhaust pipe 7, a drain tank 8, and a pipe. 9 to 15 mainly. In addition, since the hot water supply apparatus 100 of this embodiment is an exhaust suction combustion system, the burner 2, the primary heat exchanger 3, the secondary heat exchanger 4, and the fan 6 are directed from the upstream side to the downstream side of the flow of the combustion gas. Are arranged in this order.

(Burner)
Referring mainly to FIG. 1 and FIG. 2, the burner 2 is a device for generating combustion gas by burning fuel gas, and includes a combustion tube 22 having a plurality of flame holes 24. A gas supply pipe 10 is connected to the combustion pipe 22. The gas supply pipe 10 is for supplying fuel gas to the combustion pipe 22. For example, an electromagnetic valve and a proportional valve (not shown) are attached to the gas supply pipe 10. The burner 2 is also supplied with air from an opening 21 a at the bottom of the burner case 21 that houses the combustion tube 22.

  A spark plug 2 a is disposed above the combustion tube 22. The spark plug 2a is injected from the flame hole portion 24 of the combustion pipe 22 by generating an ignition spark with a target (not shown) provided in the combustion pipe 22 by the operation of an ignition device (igniter). This is for generating a flame in the fuel-air mixture. The burner 2 generates heat by burning the fuel gas supplied from the gas supply pipe 10 (this is called combustion operation).

  Referring mainly to FIGS. 5 and 6, the burner 2 mainly has a burner case 21, a plurality of combustion tubes 22, and a spark plug 2a.

  The burner case 21 is provided with an opening 21a in the bottom plate for taking air into the inside. The burner case 21 has a partition plate 21b for partitioning the air passage that enters from the opening 21a and the storage portion of the combustion tube 22. The partition plate 21b is provided with a plurality of through holes 21c, and the through holes 21c connect the air passages that enter the burner case 21 from the openings 21a and the storage portions of the plurality of combustion tubes 22. .

  Each of the plurality of combustion pipes 22 is supported by the partition plate 21 b and stored in the burner case 21. The gas inlets 23a and 23b of the plurality of combustion pipes 22 are connected to openings 21d and 21e provided on the wall surface of the burner case 21, respectively (FIG. 6).

  Above the plurality of combustion tubes 22, a spark plug 2a attached to the wall surface 21B of the burner case 21 is disposed.

  Referring mainly to FIG. 7, the combustion tube 22 mainly includes a main body unit 23, a pair of left and right burner units 22 a and 22 b, and a flame hole portion 24. The main unit 23 has gas inlets 23a and 23b. Further, a pair of burner units 22a and 22b are attached to the left and right of the main unit 23, and a flame hole 24 is provided inside the burner units 22a and 22b.

  Referring mainly to FIGS. 2 and 6, in hot water supply apparatus 100, the air around hot water supply apparatus 100 is taken into burner case 21 through an opening 21 a provided in the bottom plate of burner case 21. Part of the air that has entered the burner case 21 is mixed with the fuel gas as primary air from each of the gas inlets 23a and 23b of each of the plurality of combustion pipes 22 disposed in the burner case 21, and mixed with fuel air. The gas is supplied into the combustion tube 22 as a gas. The remaining portion of the air that has entered the burner case 21 is secondary air from the through hole 21c provided in the partition plate 21b that partitions the air passage and the storage portion of the combustion tube 22 to the storage portion of the combustion tube 22. Supplied.

  The flame hole portion 24 of the combustion pipe 22 corresponds to a combustion region in the burner case 21, and the combustion region is independently controlled so that the amount of combustion gas generated can be changed according to the required hot water supply capacity. It consists of a plurality of possible unit areas. For example, each unit region contains a different number of combustion tubes 22 and is used for combustion by independently controlling the open / closed states of a plurality of electromagnetic valves provided for each unit region. It is possible to adjust the number of the combustion pipes 22 (the number of stages of the hot water supply device). Moreover, the amount of gas supplied to the combustion pipe 22 can be adjusted steplessly within the range of the rated amount by the proportional valve provided in the gas supply pipe 10.

(Primary heat exchanger)
Referring mainly to FIG. 2, the primary heat exchanger 3 is a sensible heat recovery type heat exchanger. The primary heat exchanger 3 mainly includes a plurality of plate-like fins 3b, a heat transfer tube 3a that penetrates the plurality of plate-like fins 3b, and a case 3c that accommodates the fins 3b and the heat transfer tubes 3a therein. Have. The primary heat exchanger 3 performs heat exchange with the combustion gas generated in the burner 2, and specifically, in the heat transfer tube 3 a of the primary heat exchanger 3 by the amount of heat generated by the combustion operation of the burner 2. It is for heating the hot water flowing through.

(Secondary heat exchanger)
Referring mainly to FIG. 2, the secondary heat exchanger 4 is a latent heat recovery type heat exchanger. The secondary heat exchanger 4 is located downstream of the primary heat exchanger 3 in the flow of the combustion gas, and is connected to the primary heat exchanger 3 in series with each other. Thus, since the hot water supply apparatus 100 of this embodiment has the latent heat recovery type secondary heat exchanger 4, it is a latent heat recovery type hot water supply apparatus.

  The secondary heat exchanger 4 mainly has a drain discharge port 4a, a heat transfer tube 4b, a side wall 4c, a bottom wall 4d, and an upper wall 4g. The heat transfer tubes 4b are stacked by being spirally wound. The side wall 4c, the bottom wall 4d, and the upper wall 4g are arranged so as to surround the periphery of the heat transfer tube 4b.

  In the secondary heat exchanger 4, hot water flowing in the heat transfer pipe 4 b is preheated (heated) by heat exchange with the combustion gas after heat exchange in the primary heat exchanger 3. In this process, the temperature of the combustion gas is lowered to about 60 ° C., so that moisture contained in the combustion gas is condensed and latent heat can be obtained. Further, the latent heat is recovered by the secondary heat exchanger 4 and the moisture contained in the combustion gas is condensed to generate drain.

  The bottom wall 4 d is for partitioning between the primary heat exchanger 3 and the secondary heat exchanger 4, and is also an upper wall of the primary heat exchanger 3. An opening 4e is provided in the bottom wall 4d, and a space in which the heat transfer tube 3a of the primary heat exchanger 3 is arranged by this opening 4e and a space in which the heat transfer tube 4b of the secondary heat exchanger 4 is arranged. And communicate with each other.

  As shown by the white arrow in FIG. 2, the combustion gas can flow from the primary heat exchanger 3 to the secondary heat exchanger 4 through the opening 4 e. In this embodiment, the bottom wall 4d of the secondary heat exchanger 4 and the upper wall of the primary heat exchanger 3 are made common for simplicity, but the primary heat exchanger 3 and the secondary heat exchanger 4 An exhaust assembly member may be connected between them.

  An opening 4h is provided in the upper wall 4g, and the space in which the heat transfer tube 4b of the secondary heat exchanger 4 is arranged communicates with the internal space of the exhaust box 5 through the opening 4h. As indicated by white arrows in FIG. 2, the combustion gas can flow from the secondary heat exchanger 4 into the internal space of the exhaust box 5 through the opening 4 h.

  The drain outlet 4a is provided in the side wall 4c or the bottom wall 4d. This drain discharge port 4a is the lowest position in the space surrounded by the side wall 4c, the bottom wall 4d, and the upper wall 4g (the lowest position in the vertical direction when the hot water supply apparatus is installed), and is the lowest position of the heat transfer tube 4b. It opens below the lower end. As a result, the drain generated in the secondary heat exchanger 4 can be guided to the drain outlet 4a through the bottom wall 4d and the side wall 4c as shown by black arrows in FIG.

(Exhaust box)
Referring mainly to FIG. 2, the exhaust box 5 constitutes a combustion gas flow path between the secondary heat exchanger 4 and the fan 6. With this exhaust box 5, it is possible to guide the combustion gas after heat exchange in the secondary heat exchanger 4 to the fan 6. The exhaust box 5 is attached to the secondary heat exchanger 4 and is located downstream of the secondary heat exchanger 4 in the flow of the combustion gas.

  The exhaust box 5 mainly has a box body 5a and a fan connection portion 5b. The internal space of the box body 5a communicates with the internal space where the heat transfer tube 4b of the secondary heat exchanger 4 is disposed through the opening 4h of the secondary heat exchanger 4. The fan connection portion 5b is provided so as to protrude from the upper portion of the box body 5a. The fan connecting portion 5b has, for example, a cylindrical shape, and the internal space 5ba communicates with the internal space of the box body 5a.

(fan)
Referring mainly to FIGS. 1 and 2, the fan 6 mainly has a fan case 61, an impeller 62, a drive source 63, and a rotating shaft 64. The drive source 63 is provided outside the fan case 61, and the rotating shaft 64 connects the impeller 62 accommodated in the fan case 61 and the drive source 63 provided outside the fan case 61. As a result, the impeller 62 can rotate around the rotation shaft 64 by being given a driving force from the driving source 63.

  The fan 6 is arranged downstream of the heat exchanger (primary heat exchanger and secondary heat exchanger) in the flow direction of the combustion gas, and is configured to draw air into the burner 2. Further, the fan 6 sucks the combustion gas after passing through the secondary heat exchanger 4 (heat exchanged in the secondary heat exchanger 4) and discharges it to the outside of the hot water supply device 100. It is connected to the exhaust pipe 7 located outside. The exhaust pipe 7 is disposed outside the hot water supply apparatus 100 and is connected to the outer peripheral side of the fan case 61. For this reason, the combustion gas discharged to the outer peripheral side of the impeller 62 can be discharged to the outside of the hot water supply apparatus 100 through the exhaust pipe 7.

  In this way, the fan 6 is located downstream of the exhaust box 5 and the secondary heat exchanger 4 in the flow of the combustion gas. That is, in the hot water supply device 100, the burner 2, the primary heat exchanger 3, the secondary heat exchanger 4, the exhaust box 5, and the fan 6 are arranged in order from the upstream side to the downstream side of the flow of combustion gas generated in the burner 2. Are lined up. In this arrangement, since the combustion gas is sucked and exhausted by the fan 6 as described above, the hot water supply apparatus 100 of this embodiment is an exhaust suction combustion type hot water supply apparatus.

(Drain discharge route)
Referring mainly to FIG. 1 and FIG. 4, the drain discharge path in the hot water supply apparatus of the present embodiment is constituted by a drain discharge port 4 a, a pipe 9, a drain tank 8, and a drain discharge pipe 14. The drain tank 8 is for storing the drain generated in the secondary heat exchanger 4. The drain tank 8 mainly has a drain storage part 8a, a wall part 8b, a drain introduction part 8d, a drain discharge part 8e, and a drain outlet 8f.

  The internal space of the drain storage portion 8a is partitioned into spaces 8A and 8B by a wall portion 8b. The space 8A and the space 8B are partitioned by a wall portion 8b and communicate with each other through a hole 8c provided on the lower side of the wall portion 8b. The drain introduction part 8d is provided above the drain storage part 8a so as to communicate with the space 8A, and the drain discharge part 8e is provided at a predetermined height position of the drain storage part 8a so as to communicate with the space 8B.

  In order to discharge the drain in the secondary heat exchanger 4 to the outside, the drain discharge port 4a of the secondary heat exchanger 4 and the drain introduction part 8d (FIG. 4) of the drain tank 8 are connected by a pipe 9. Yes. Further, the drain discharge pipe 14 is connected to a drain discharge portion 8e (FIG. 4) of the drain tank 8 and communicates with the outside of the hot water supply apparatus 100 (FIG. 1). The acidic drain stored in the drain tank 8 is temporarily stored in the internal space of the drain tank 8 and then normally discharged from the drain discharge pipe 14 to the outside of the hot water supply apparatus 100.

  The drain tank 8 has a water seal structure. In other words, when the drain water level stored in the lower part of each of the space 8A and the space 8B becomes higher than the upper end of the hole 8c as shown by a two-dot chain line in the figure, the drain tank 8 enters the drain tank 8 from the drain discharge portion 8e. The outside air that has entered (air outside the hot water supply apparatus 100) does not enter the drain introduction portion 8d side. The water seal structure of the drain tank 8 prevents outside air from passing through the drain tank 8 and entering the hot water supply apparatus 100 as indicated by white arrows in the figure.

  A drain outlet 8f (FIG. 4) is provided in the lower part of the drain tank 8 (space 8B). The drainage pipe 15 is connected to the drainage port 8f and communicates with the outside of the hot water supply apparatus 100 (FIG. 1). For drainage piping 15 (normally closed), drainage in drain tank 8 that cannot be discharged from drain discharge piping 14 is opened by opening drain removal piping 15 for maintenance and freeze prevention. Designed to be discharged. The interior space of the drain tank 8 may be filled with a neutralizing agent (not shown) for neutralizing acidic drain.

(Plumbing)
Referring mainly to FIGS. 1 and 2, the water supply pipe 11 is connected to one end of the heat transfer pipe 4 b of the secondary heat exchanger 4, and the tapping pipe 12 is one of the heat transfer pipes 3 a of the primary heat exchanger 3. Connected to the end. Further, the other end of the heat transfer tube 3 a of the primary heat exchanger 3 and the other end of the heat transfer tube 4 b of the secondary heat exchanger 4 are connected to each other by a connection pipe 13. Each of the gas supply pipe 10, the water supply pipe 11, and the hot water supply pipe 12 communicates with the outside at the upper part of the hot water supply apparatus 100, for example. The burner 2, the primary heat exchanger 3, the secondary heat exchanger 4, the exhaust box 5, the fan 6, the drain tank 8, and the like are disposed in the housing 1.

  Referring mainly to FIG. 1, the gas supply pipe 10 is connected to the burner 2. The water supply pipe 11 is connected to the heat transfer pipe 4b (see FIG. 2) of the secondary heat exchanger 4, and the hot water supply pipe 12 is connected to the heat transfer pipe 3a (see FIG. 2) of the primary heat exchanger 3. Further, the heat transfer tube 3 a of the primary heat exchanger 3 and the heat transfer tube 4 b of the secondary heat exchanger 4 are connected to each other by a connection pipe 13. Each of the gas supply pipe 10, the water supply pipe 11, and the hot water supply pipe 12 communicates with the outside at the upper part of the hot water supply apparatus 100, for example.

(Control part)
Referring to FIG. 8, hot water supply apparatus 100 of the present embodiment further includes a control unit 200 for controlling a flame generated in the combustion region of burner 2. The control unit 200 is configured by, for example, a microcomputer and a hybrid integrated circuit (HIC).

  The calculation unit 201 of the control unit 200 is connected to the feed water thermistor 11a, the hot water thermistor 12a, and the proportional valve 10b. The supply current value can be detected. The calculation unit 201 is connected to the storage unit 202 and can store data processed by the calculation unit 201, threshold value data necessary for water seal determination (permission determination), and the like. The water seal determination unit 203 includes the calculation unit 201 and the storage unit 202.

  The command unit 204 of the control unit 200 is connected to the fan 6, the spark plug 2a, the original solenoid valve 10a, the proportional valve 10b, and the solenoid valve 10c. The control unit 200 is configured to be able to control the operation of each unit connected to the command unit 204, the rotational speed of the fan 6, the opening degree of the proportional valve 10b, and the like through commands from the command unit 204.

  In this way, the control unit 200 increases the rotational speed of the fan 6 and blows combustion air to the combustion region 25 (combustion pipe 22), and opens the original solenoid valve 10a, the proportional valve 10b, and the solenoid valve 10c. An air-fuel mixture containing fuel gas can be supplied to the burner 2. Further, the control unit 200 can ignite the spark plug 2a, and thereby, the fuel-air mixture can be burned to generate a flame in the burner 2. The control unit 200 is configured to be able to extinguish a flame generated in the burner 2 by closing the original solenoid valve 10a, the proportional valve 10b, and the solenoid valve 10c and stopping the supply of the fuel gas to the burner 2.

  The original solenoid valve 10a can supply and stop fuel gas to the burner 2, and the proportional valve 10b can adjust the supply amount of fuel gas according to the supply current amount. The plurality of solenoid valves 10 c are connected to each of the unit regions 26 that constitute the combustion region 25 in the burner case 21. Each unit region 26 accommodates a different number of combustion tubes 22, and the number of combustion tubes 22 used for combustion is adjusted by independently controlling the open / closed states of the plurality of solenoid valves 10c. It is possible.

  Further, the water supply pipe 11 has a water supply thermistor 11a that measures the temperature of the water supply, and the hot water supply pipe 12 has a hot water thermistor 12a that measures the temperature of the hot water. The water supply thermistor 11 a and the hot water thermistor 12 a are connected to the calculation unit 201 of the control unit 200. The proportional valve 10b is also connected to the calculation unit 201, and the calculation unit 201 can detect the amount of fuel gas supplied to the combustion region from the amount of current supplied to the proportional valve 10b.

  The water seal determination unit 203 calculates the estimated drain discharge amount based on the measurement value of each unit connected to the calculation unit 201, and the drain is determined on the condition that the calculated estimated drain discharge amount has reached a predetermined threshold or more. The discharge path is in a water-sealed state, and it is configured to determine (permit determination) that the hot water supply device can be permitted to operate in the normal mode.

  Specifically, for example, the calculation unit 201 uses the temperature of the hot water measured by the hot water thermistor 12a, the temperature of the hot water measured by the water supply thermistor 11a, and the supply amount of the fuel gas detected from the proportional valve 10b. The estimated drain discharge amount can be calculated based on a predetermined calculation table, and the estimated drain discharge amount can be calculated by comparing the calculated estimated drain discharge amount with a predetermined threshold value stored in advance in the storage unit 202. It is configured so that permission can be determined on the condition that a predetermined threshold value or more has been reached. As a result, the permission determination can be automatically performed by the water seal determination unit 203. Although the case where the estimated drain discharge amount is calculated using the temperature of the hot water, the temperature of the feed water, and the supply amount of the fuel gas has been described here, the estimated drain discharge amount is not necessarily calculated using all the detected values. The estimated drain discharge amount may be calculated using at least one of the temperature of the hot water, the temperature of the feed water, and the supply amount of the fuel gas.

  Further, the exhaust pipe 7 located on the downstream side of the flow direction of the combustion gas with respect to the heat exchanger may have an exhaust temperature detection part 7a for measuring the temperature of the exhaust gas (combustion gas). The exhaust temperature detection unit 7 a is connected to the calculation unit 201 of the control unit 200. The water seal determination unit 203 has an exhaust temperature (combustion gas temperature) in which the exhaust temperature measured by the exhaust temperature detection unit 7a is calculated based on a predetermined calculation table from the gas supply amount detected from the proportional valve current. However, if it is lower than a predetermined threshold value stored in advance in the storage unit 202, the permission determination is not performed, and the exhaust temperature is calculated so that the permission determination is performed on the condition that the predetermined threshold value or more is reached. It is configured to be possible. As a result, the permission determination can be automatically performed by the water seal determination unit 203. In the water seal determination method using the exhaust temperature, when the drain discharge path is in a water seal state, the temperature of the combustion gas substantially matches the exhaust temperature calculated from the gas supply amount based on a predetermined calculation table. On the other hand, when the drain discharge path is not sealed with water, outside air having a temperature lower than that of the combustion gas is taken into the hot water supply device from the drain discharge path, so that the temperature of the exhausted combustion gas decreases. doing. Instead of calculating the exhaust temperature and comparing it with the threshold value, the temperature change detected by the exhaust temperature detection unit 7a is constantly monitored during the water seal determination mode, and the detected temperature suddenly increases at a certain timing. A drain water seal may be determined (permission determination).

  When performing water seal determination using the above-described water supply thermistor 11a, hot water thermistor 12a, etc., the exhaust temperature detector 7a is not necessarily used for water seal determination, and vice versa. In addition to this, when the internal pressure of the hot water supply device is detected by a pressure sensor provided in the hot water supply device 100 (in the combustion gas flow path) and the internal pressure falls below a predetermined threshold value, It is also conceivable that the determination unit 203 performs permission determination.

[Burner operation]
Next, the operation of the burner 2 in the hot water supply apparatus 100 of this embodiment will be described mainly with reference to the flowchart shown in FIG. 9 and the timing chart shown in FIG.

  In the hot water supply apparatus according to the present embodiment, the control unit is configured so that the burner is not sealed until the water seal determination unit 203 performs permission determination that the drain discharge path is sealed with water and the hot water supply apparatus operates in the “normal mode” described below. A command is issued to operate the water heater in the following “water seal determination mode” so as to perform intermittent operation.

  When restarting a new hot water supply device, a hot water supply device that has not been used for a long time, or a hot water supply device that has been drained for maintenance or freezing prevention, the elapsed time from the previous use or Based on the pressure in the hot water supply system, the amount of water in the drain tank, etc., the operation in the water seal judgment mode may be automatically started. The start of operation in the water seal determination mode may be selected.

(Water seal judgment mode)
In the water seal determination mode, the burner performs intermittent operation. Here, when a water amount sensor (not shown) provided in the water supply pipe detects a minimum working water amount or more, the ON / OFF control of the burner 2 of the hot water supply device 100 is turned ON, but the intermittent operation is the ON of the burner. This means that the burner repeatedly starts and stops when the / OFF control is ON (FIG. 10). The operation of the burner may include not only the combustion operation in the burner but also a series of operations necessary for the combustion operation, and includes repeating the operation and stop of the fan in cooperation with the operation of the burner. May be.

  Referring to FIG. 9, for example, when a hot water tap to be used is opened and a water amount sensor (not shown) provided in the water supply pipe detects a minimum working water amount or more, the operation of the burner 2 is started (step S1). .

  When starting the operation of the burner 2, first a pre-purge (operation to start the fan operation before ignition and remove the residual gas in the combustion chamber) for a certain period of time, then open the original solenoid valve and open the proportional valve. The degree of opening required for ignition is opened, the solenoid valves connected to all the combustion pipes are opened sequentially, the ignition device (igniter) is operated to generate an ignition spark from the spark plug, and the combustion pipe is ignited. In this way, the operation of the burner is started.

  During operation of the burner, the original solenoid valve is opened, the opening of the proportional valve is maximized, and all solenoid valves are opened, with the maximum capacity to supply the maximum amount of fuel gas to all the combustion tubes. Maintain the combustion state. In this way, by maintaining the combustion state at the maximum capacity, the amount of drain generation is maximized, so that the drain discharge path can be quickly sealed with water. That is, even when the water seal of the drain discharge path is released, it is possible to quickly exhibit the desired hot water supply capacity as usual.

  Next, after a certain period of time has elapsed with the burner activated (combustion state), all the original gas solenoid valve, gas proportional valve and gas solenoid valve (distribution valve) are automatically closed and extinguished, and post-purge ( After the fire extinguishing, the operation of removing the residual gas in the combustion chamber without stopping the fan is performed for a certain period of time, and then the operation of the burner is terminated (step S2).

  Next, in the above-described water seal determination unit 203 (FIG. 8), it is determined (permission determination) whether or not the drain discharge path is sealed and the hot water supply device can be permitted to operate in the following “normal mode” ( Step S3).

  If the permission determination is not made in step S3, the process returns to step S1, and after a predetermined time has elapsed from the end of the operation of the burner, after performing the pre-purge again for a predetermined time, the original gas solenoid valve, the gas proportional valve and the gas solenoid valve are opened. Ignite the combustion tube. Thereafter, until the drain discharge path is sealed with water and the permission determination is performed by the water seal determination unit 203, the above operation is repeated and the burner is operated intermittently as shown in the timing chart of FIG.

  In the present embodiment, after the stop of the burner and the stop of the fan in step S2, by providing a certain pause period during which the fan is not operating, the suction of outside air from the drain discharge path is stopped during this period. The drain generated in the secondary heat exchanger 4 can be stored in the drain tank 8 or the like.

  On the other hand, when the drain discharge path is sealed with water in Step S3 and the water seal determination unit 203 performs permission determination, the normal mode is changed to the following (Step S4). 9 and 10 show the case where the permission determination is performed by the water seal determination unit 203 in a state where the burner is not operating, the permission determination by the water seal determination unit 203 during the operation of the burner. In this case, after the permission determination is made, the state may be shifted to a state where the burner in the normal mode is in operation.

(Normal mode)
When a water amount sensor (not shown) provided in the water supply pipe detects a minimum working water amount or more, ON / OFF control of the burner 2 of the hot water supply device 100 is turned on, but when the hot water supply device (burner) is operated in the normal mode. Means that when the ON / OFF control of the burner is ON, the burner can be continuously operated as long as there is no abnormality in the hot water supply apparatus. That is, the operation of the burner is continued until the ON / OFF control of the burner is turned OFF, and the burner is stopped when the ON / OFF control of the burner is turned OFF. The operation of the burner may include not only a combustion operation in the burner but also a series of operations necessary for a combustion operation such as a fan operation linked to the operation of the burner.

  Referring to FIG. 9, after the mode is changed to the normal mode in step S <b> 4, the operation of burner 2 of hot water supply apparatus 100 is automatically started after a predetermined time has elapsed from the end of the operation of the burner in previous step S <b> 2 ( Step S5).

  Referring to FIG. 10, when the operation of the burner 2 is started, first, the pre-purge is performed for a certain period of time, and then the original solenoid valve, the proportional valve, and the solenoid valve (the solenoid connected to the unit region provided with at least the spark plug 2a) Valve) is opened, an ignition device (igniter) is operated to generate an ignition spark from the spark plug 2a, and the combustion pipe is ignited.

  After the burner 2 is started (during operation), the hot water is detected while detecting the water temperature by the water supply thermistor 11a, the water amount by the water supply sensor (not shown), and the hot water temperature by the hot water thermistor 12a. The number of combustion pipes (the number of stages of the hot water supply device) is adjusted by opening and closing a plurality of solenoid valves so that the temperature becomes the set temperature, and the amount of fuel gas supplied to the combustion pipes is adjusted by a proportional valve (step S6).

  Next, for example, when the hot water tap that has been used is closed and the water amount sensor detects that the amount of water is less than the minimum operating water amount, the ON / OFF control of the burner 2 is turned OFF, and the operation of the burner 2 is ended (step S7). Referring to FIG. 10, when the operation of burner 2 is finished, first, all of the original gas solenoid valve, the gas proportional valve and the gas solenoid valve are closed and extinguished, and after the post purge is performed for a certain period of time, the fan is stopped. .

<Embodiment 2>
The structure of the hot water supply apparatus in Embodiment 2 of this invention is demonstrated with reference to FIGS. The hot water supply apparatus of the present embodiment is configured such that the fan 6 is disposed upstream of the heat exchanger in the flow direction of the combustion gas and pushes air into the burner, and the fan 6 serves as a heat exchanger. The exhaust gas hot water supply device is configured to discharge combustion gas after passing through the outside of the hot water supply device by pushing air. For this reason, the fan 6, the burner 2, the primary heat exchanger 3, and the secondary heat exchanger 4 are arrange | positioned in this order toward the downstream from the upstream of the flow of combustion gas. Although the present embodiment is different from the first embodiment in this respect, the other points are basically the same as those in the first embodiment, and thus the description overlapping with the first embodiment is omitted.

  In the hot water supply apparatus 100 according to Embodiment 1 of the exhaust suction system, the outside air is prevented from entering the hot water supply apparatus 100 through the drain tank 8 due to the water seal structure of the drain tank 8. In the present embodiment, due to the water seal structure of the drain tank 8, particularly when the hot water supply apparatus is installed indoors, the combustion gas generated inside the hot water supply apparatus 100 passes through the drain tank 8 to the outside of the hot water supply apparatus 100 ( Leakage into the indoor space is prevented.

  In the present embodiment, even during the period until the drain discharge path is sealed with water, the combustion gas is continuously discharged into the room or the like by operating the burner 2 intermittently as in the first embodiment. Can be prevented.

  In addition, in the hot water supply apparatus 100 of the present embodiment of the exhaust push-out method, since the outside air is not sucked from the drain discharge path, after the burner is stopped and the fan is stopped in step S2 in the operation of the burner in the water seal determination mode. It is not always necessary to provide a certain pause period during which the fan does not operate. Even if the fan continues to operate, it is possible to store the drain generated in the secondary heat exchanger 4 in the drain tank 8 or the like. is there.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 100 Hot-water supply apparatus, 1 housing | casing, 2 burner, 2a Spark plug, 21 Burner case, 21a Opening part, 22 Combustion pipe, 22a, 22b Burner unit, 23 Main body unit, 23a, 23b Gas inlet, 24 Flame hole part, 25 Combustion region, 26 unit region, 200 control unit, 201 calculation unit, 202 storage unit, 203 water seal determination unit, 204 command unit, 3 primary heat exchanger, 3a, 4b heat transfer tube, 3b fin, 3c case, 4 secondary Heat exchanger, 4a drain outlet, 4c side wall, 4d bottom wall, 4e, 4h opening, 4g top wall, 5 exhaust box, 5a box body, 5b fan connection, 5ba internal space, 6 fans, 7 exhaust pipe, 7a Exhaust temperature detector, 8 Drain tank, 9 piping, 10 Gas supply piping, 10a Original solenoid valve, Proportional valve 10b, 10c Electromagnetic Valve, 11 Water supply piping, 11a Water absorption thermistor, 12 Hot water piping, 12a Hot water thermistor, 13 Connection piping, 14 Drain discharge piping, 15 Drain discharge piping, 61 Fan case, 62 Impeller, 63 Motor, 64 Rotating shaft.

Claims (6)

A latent heat recovery type hot water supply device capable of heating hot water by recovering the latent heat of combustion gas,
A burner for generating the combustion gas by burning the fuel gas in the combustion region;
A heat exchanger that heats hot water flowing inside by heat exchange with the combustion gas generated in the burner;
A fan for supplying air to the burner;
A drain discharge path connected to the heat exchanger in order to discharge drain generated by collecting latent heat in the heat exchanger to the outside of the heat exchanger;
The drain discharge path has a water seal structure that is sealed with the drain,
The burner includes a water seal determination unit that performs permission determination that the drain discharge path is sealed and the hot water supply device operates in a normal mode, and the burner determines until the water seal determination unit performs the permission determination. A hot water supply apparatus comprising: a control unit that issues a command so that the burner repeats operation and stop when the ON / OFF control is ON . In the burner, the combustion region is composed of a plurality of unit regions that can be independently controlled so that the amount of combustion gas generated can be changed according to the required hot water supply capacity,
The hot water supply apparatus according to claim 1, wherein the control unit issues a command to the burner so that the entire unit region is combusted until the water seal determination unit performs the permission determination. The burner is configured to be able to adjust the supply amount of the fuel gas to the combustion region,
The hot water supply apparatus according to claim 1 or 2, wherein the control unit issues a command to the burner so that a supply amount of the fuel gas is maximized until the water seal determination unit performs the permission determination. .   The water seal determination unit includes at least one selected from the group consisting of a supply amount of the fuel gas to the combustion region, a water temperature supplied to the hot water supply device, and a hot water temperature discharged from the hot water supply device. The hot water supply apparatus according to any one of claims 1 to 3, wherein the permission determination is performed on the condition that the estimated drain discharge amount calculated by using a predetermined threshold value or more has been reached. The fan is arranged downstream of the heat exchanger in the flow direction of the combustion gas and configured to draw air into the burner,
An exhaust gas temperature detector for measuring the temperature of the combustion gas further downstream of the heat exchanger in the flow direction of the combustion gas;
The said water seal determination part performs the said permission determination on the conditions that the temperature of the said combustion gas measured by the said exhaust gas temperature detection part showed the increase tendency more than a predetermined threshold value, Any one of Claims 1-3 A hot water supply apparatus according to claim 1.   The hot water supply according to any one of claims 1 to 4, wherein the fan is arranged upstream of the heat exchanger in a flow direction of the combustion gas and pushes air into the burner. apparatus.

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